Altitude and Allergy to House-Dust Mites: A Paradigm of the Influence of Environmental Exposure on Allergic Sensitization

Abstract

To further investigate the possibility of a cause and effect relationship between exposure to house-dust mite (HDM) allergens and respiratory disease associated with dust mite sensitivity, we compared schoolchildren living in the Alps, where exposure to HDM is low, with those living at sea level, where it is high. The study included 933 schoolchildren from the fourth and fifth grades. The protocol included the standardized 1978 American Thoracic Society (ATS) questionnaire for children, skin testing using common aero-allergens and controls, and antigenic measurements of dust samples from mattresses (Group I antigen). The prevalence of asthma with positive skin test to HDM and the overall prevalence of positive skin test to HDM were significantly lower in mountain schoolchildren. The mean geometric HDM antigenic level in mattresses was much lower in the Alps (0.36 micrograms/g dust) than at sea level (15.8 micrograms/g dust). In contrast, the prevalence of hay fever and positive skin test to grass pollens as well as the overall prevalence of positive skin tests to grass pollens were significantly higher in the Alps. These data illustrate a striking relationship between exposure to environmental allergens and atopic sensitization.

Assessment of personal and community-level exposures to particulate matter among children with asthma in Detroit, Michigan, as part of Community Action Against Asthma (CAAA).

“…Considerable research evidence suggests that both indoor and outdoor environmental exposures may be involved in the worldwide increase in asthma (15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25). Some of the strongest associations have been found with indoor allergens such as dust mite and cockroach in children sensitized to that particular allergen (24)(25)(26)(27)(28)(29)(30)(31)(32). Exposure to environmental tobacco smoke, both in utero (15,19) and during childhood (17,18,20), also appears to play an important role in asthma causation and aggravation.…”

Associations among high altitude, allergic rhinitis, and bronchial hyperreactivity

“…[8] More than half of all dust samples (53.3%) were collected at altitudes below 1500 m. [8] Another study performed at over 1500 m in the Alps found that positive HDM skin test results were significantly fewer in mountain schoolchildren, and the levels of HDM antigens in mattresses were much lower than those at sea level. [7] One study evaluated the prevalence of allergic diseases (rhinoconjunctivitis and asthma) in 3196 children living 3658 m above sea level in Lhasa, Tibet. The prevalence of "wheezing at any time", "diagnosed asthma", and "current wheezing" was 1.4, 1.1, and 0.8% respectively.…”

“…But HA exerts a therapeutic effect in those with allergic airway diseases; the air is fresh, with low levels of pollen and HDMs. [4][5][6][7] The prevalence of pediatric allergic rhinoconjunctivitis and asthma were evaluated (in conformity with the ISAAC Phase III guidelines) at an altitude of 3658 m in Lhasa, Tibet. The frequencies of allergic respiratory symptoms were evaluated in natives (3190 students) who were asked if they "experienced an asthma attack", "were wheezing", and "had asthma"; the prevalence of these conditions was 1.4%, 0.8%, and 1.1%, respectively.…”

“…[4][5][6][7] HA reduces supposedly the incidence of allergic respiratory disease. The daily symptoms of asthma and the extent of bronchial obstruction are significantly less in children living in mountainous areas.…”

“…[5] Reduced air pollution, humidity, pollen and house dust mite (HDM) concentrations facilitate airway recovery. [6,7] However, some studies found that HA did not benefit those with allergic respiratory disease. [8][9][10] We sought associations among HA, allergic rhinitis, and bronchial hyperreactivity in which relevant literature was reviewed.…”